Circuit assembly for down converter for satellite communications

ABSTRACT

A microminature down converter for satellite communications has a structure in which high frequency circuit printed boards (5) are respectively arranged on peripheral four surfaces of a box made of a die-casting and a power printed board (1) for supplying power to each of said high frequency circuit printed boards is disposed on a surface opposite to an input portion of a wave guide tube, whereby power supply to each of the high frequency circuit printed boards (5) is performed not through lead wires. Therefore, electromagnetic couplings occurring between printed boards are prevented and electromagnetic couplings between high frequency signals occurring in the printed boards and lead wires are also prevented, so that it is possible to restrain occurrence of undesired waves.

DESCRIPTION MICROMINATURE DOWN CONVERTER FOR SATELLITE COMMUNICATIONS

1. Technical Field

The present invention relates to a microminature down converter forsatellite communications which is used to receive satellitecommunications.

2. Background Art

Generally, in microminature down converters for satellitecommunications, high frequency circuit printed boards and power printedboard for supplying power thereto are disposed at two or threeperipheral surfaces of a box made of a die-casting and the power issupplied from the power printed board to each of the high frequencycircuit printed boards through, mainly, lead wires.

However, the structure in which the power is supplied to each of thehigh frequency circuit printed boards through the lead wires asdescribed above has a problem that the lead wires and high frequencysignals occurring in the high frequency circuit printed boardselectromagnetically couple with each other, whereby undesired wavesappear in intermediate frequency outputs, which can be obtained afterreceived input signals are frequency converted and it is very difficultto remove the undesired waves.

In view of such problem, the present invention has been accomplished andan object of the invention is to provide a superior microminature downconverter for satellite communications which has a structure to supplypower to each of high frequency circuit boards not through lead wiresand in which occurrence of undesired waves is restrained.

DISCLOSURE OF INVENTION

A microminature down converter for satellite communications according tothe invention is characterized in that high frequency circuit printedboards are disposed at peripheral four surfaces of a box made of adie-casting and a power printed board which supplies power to each ofthe high frequency circuit printed boards not through lead wires isdisposed on a surface opposite to an input portion of a wave guide tube.

The microminature down converter of the invention has a structure inwhich the high frequency circuit printed boards are disposed at theperipheral four surfaces of the box made of a die-casting, so thatelectromagnetically couplings occurring between respective printedboards are prevented and further electromagnetically couplings betweenhigh frequency signals occurring in the respective printed boards andthe lead wires is also prevented by the fact that the power to therespective printed boards is supplied not through lead wires, whereby itis possible to restrain occurrence of the undesired waves.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing an embodiment of theinvention;

FIG. 2 is a sectional view showing a mounting condition of theembodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the invention will be described withreference to the accompanying drawings. FIG. 1 is an explodedperspective view showing an embodiment of the invention and FIG. 2 is asectional view showing a mounting condition of the embodiment. In thesedrawings, the reference numeral 1 denotes a power printed board forsupplying power, 2 denotes fixing plates which are used to fixfeed-through capacitors, 3 denotes feed-through capacitorsinterconnecting the power printed board and high frequency circuitprinted boards, 4 denotes holes, into which the feed-through capacitorsare inserted, formed in a box made of a die-casting, 5 denotes the highfrequency circuit printed boards and 6 denotes covers for the highfrequency circuit printed boards to shield the high frequency circuitprinted board.

In the embodiment, the high frequency circuit printed boards 5 receivepower supply from the power printed board 1 through the feed-throughcapacitors 3 which are fixed on the box by the plates 2 for fixing thefeed-through capacitors, without using any lead wires which are apt tocause electromagnetic coupling. Therefore, occurrence of undesired wavesis restrained.

Further, electromagnetic coupling between the high frequency circuitprinted board 5 and the other three high frequency circuit printedboards 5 respectively disposed on the other three surfaces is alsoprevented by threadedly fixing the covers 6 made of aluminum for highfrequency circuit printed board on the box so as to cover respectivehigh frequency circuit printed boards.

Further, in the above described embodiment, the feed-through capacitorsare fixed on the box by using the plates for fixing the feed-throughcapacitors but the same advantages can be obtained even when screwfixing type feed-through capacitors which are directly fixable on thebox are used without using the plates for fixing the feed-throughcapacitors.

INDUSTRIAL APPLICABILITY

As described hereinbefore, according to the invention, it is possible torestrain the undesired waves, which occur from the electromagneticcoupling, by the reason that the power printed board and the highfrequency circuit printed boards are interconnected not through leadwires and the high frequency printed circuit boards are respectivelyarranged at the for peripheral surfaces of the box and covered by thecovers made of aluminum. It is possible to say that the presentinvention is a very effective invention in practice.

We claim:
 1. A circuit assembly for a down converter for satellitecommunications, said circuit assembly comprising:a box shaped housing;at least one first printed circuit board arranged on at least one firstsurface of said box shaped housing; a power printed circuit boardarranged on a second surface of said box shaped housing; at least onefeed-through capacitor fixed on said second surface of said box shapedhousing and interconnecting said at least one first printed circuitboard and said power printed circuit board to supply power from saidpower printed circuit board to said at least one first printed circuitboard; and at least one fixing plate disposed on said second surface ofsaid box shaped housing between said box shaped housing and said powerprinted circuit board, said at least one feed-through capacitor beingmounted in said at least one fixing plate.